In a stereoscopic image pick-up apparatus, with the use of two image pick-up units which are arranged with a parallax to the right and left, the same subject is photographed from right and left points of view, and an image for a left eye and an image for a right eye are acquired, respectively. The right and left images thus acquired are inputted to a three-dimensional (3D) display capable of displaying in a 3D manner, and are displayed so as to be viewable separately by the right and left eyes, whereby the right and left images can be recognized as a stereoscopic image.
Normally, optical systems having the same performance and characteristics are used as photographing optical systems of the two image pick-up units, and the respective photographing optical systems are adjusted and incorporated in an apparatus main body so that optical axes thereof coincide with each other.
However, there is individual variability between the two photographing optical systems. Therefore, when a change in zoom factor together with a lens movement or the like is performed, there arises a problem that the optical axes of the two photographing optical systems deviate in accordance with a zoom position. In addition, it is extremely difficult to mechanically adjust the optical axes so that the optical axis deviation does not occur over an entire zoom range.
Up to now, in order to solve this problem, there has been proposed a stereoscopic image pick-up apparatus in which: storage means which stores therein optical axis deviation of the two photographing optical systems for each zoom position is provided; corresponding optical axis deviation is read out from the storage means in accordance with the zoom positions of the photographing optical systems at the time of photographing; coordinates of one image of the photographed right and left images are converted on the basis of the read-out optical axis deviation; and accordingly, coordinates of optical axes of the right and left images are made coincident with each other (PTL 1).
In addition, PTL 2 discloses a stereoscopic image pick-up apparatus including: a first lens barrel including a CCD for obtaining photographing information on a right eye; a second lens barrel including a CCD for obtaining photographing information on a left eye; a camera detection circuit which detects focal lengths of the first lens barrel and the second lens barrel; a ROM which is formed of an EEPROM and the like, and stores therein in advance a deviation amount of an optical axis center of each of the first lens barrel and the second lens barrel for each focal length; and a CPU which controls an image cut-out area within at least one of the paired right and left CCDs for each focal length on the basis of an output from the ROM.
On the other hand, PTL 3 discloses an image processing apparatus in which: an approximate expression for coordinate correction with respect to a lens center as the reference is set to lens characteristics of a stereo camera; and projection coordinates of a target image captured by the camera are corrected on the basis of the approximate expression.